Why should I ?

As you already know that roundSlider is completely free for both commercial and non-commercial use.

I belive that I have provided the good plugin, also provided my maximum level of support to clarify your queries till date.

If you felt that roundSlider was really helpful to your project, and you want to give me a appriciation then you can consider a donation.

Don't worry about how much money contributing, even a small amount also makes me happy and proud...!